How to grant edit access only to set of users defined in a cck field of a node?

Question

I am trying to restrict edit(node/%nid/edit) access only to users defined in one of the node fields. can I use hook menu alter for node/%nid/edit so i can write a custom access callback or use hook node access to achieve it. One thing to mention here is any user can comment on that node and when they save the comment, I am updating some fields on the node and saving it thru node_save. What will be the best way to achieve this access restriction.

Answer 1

As per me the best way to restrict the edit access would be by implementing hook_node_access, something like the following:

function MODULE_node_access($node, $op, $account) {
  if ($op == 'update' && $node->type == 'YOUR_TYPE' && $node->field_custom[LANGUAGE_NONE][0]['value'] == 'some value') {
    return NODE_ACCESS_ALLOW;
  }
  else {
    return NODE_ACCESS_DENY;
  }

}

Answer 2

I'm not sure if it'll be considered as the best way, but a possible way to address your question is to use the Rules module, and a rule that is a variation of the rule I included (in export format) in my answer to the question about How to restrict access to a node via node/12 and allow access via a path like content/sometitle?

These are the changes to that rule to make it work for this case also:

• Append /edit at the end anywhere there is already something like node/%.
• Add a Rules 'Condition' to verify your "... access only to users defined in one of the node fields".
• Change the "Message" (in the Rules 'Action') to something that fits your needs.
• Modify the Rules 'Action' to fit your own requirements, e.g. to issue a redirect to some other page.

Haven't experimented/tried creating this rule (= variation of the rule in the answer I mentioned above). But pretty sure it'll work.